Not Just for Paint Chips Anymore. High Throughput, Open Vessel Microwave Digestion of Matrices Requiring Moderate Conditions

Transcription

1 Not Just for Paint Chips Anymore High Throughput, Open Vessel Microwave Digestion of Matrices Requiring Moderate Conditions

2 Objective Develop a sample preparation procedure for analysis of a range of sample types Meet laboratory needs for increased throughput and turn around time Development of a safe, inexpensive, disposable microwave vessel system

3 A Novel Microwave Approach to a Difficult Problem Instrumentation CEM MDS/MARS Microwave Digestion System Fiberoptic Temperature Control CEM DV-50 High Throughput Vessel Set (P/N ) *Turntable adapter must be used in the MARS.

4 DV-50 Vessel

5 DV-50 Vessel Accessory Set Specifications Sample Capacity: 1-36 vessels Vessel: open disposable 50 ml centrifuge tube Operating temperature: 115 C

6 DV-50 Vessel Accessory Set 52 Vessel Turntable

7 Sample Types Paint Chips - ELPAT ** Round 010 Soils - ELPAT ** Round 010 Wipes - ELPAT ** Round 010 ** Environmental Lead Proficiency Analytical Testing Reference MaterialM

8 Procedure Weigh sample directly into DV-50 tube * Add nitric acid ** Heat at 115 C C for min. *** Allow to cool Dilute to the 50 ml mark with DI water Shake Centrifuge Aspirate directly into ICP or AA * paint chips (0.1 g), soils (0.1 g) ** paint chips (5 ml), soils (10 ml) *** paint chips (15 min.), soils (30 min.)

9 ELPAT Paint Chip Lead Recoveries DV 50 Lead Values Certificate Lead Values Range Sample ID Mean * % RSD Low High % RSD (Wt. %) (Wt. %) (Wt. %) Sample Sample Sample Sample * 36 digestions

10 ELPAT Soil Lead Recoveries DV 50 Lead Values Certificate Lead Values Range Sample ID Mean * % RSD Low High % RSD (Wt. %) (Wt. %) (Wt. %) Sample Sample Sample Sample * 36 digestions

11 ELPAT Wipe Lead Recoveries Sample ID Wipe 1 Wipe 2 Wipe 3 Wipe 4 Wipe 5 Wipe 6 DV 50 Lead Results Lead Value (ppm) Certificate Lead Values Certified Lead Value (ppm) Range Low High

12 DV ml High Throughput Vessel with filter basket

13 Baby Wipes Procedure Place wipe into DV-50 tube Spike with 100uL of 1000 ug/ml Pb standard Add 10 ml HNO 3 and place basket into vessel Heat at 110 C for 20 minutes Cool and remove basket Dilute to 50 ml and filter. Analyze by ICP

14 Baby Wipes Lead Spike Recoveries n Spike Recovery RSD ug/ml % %

15 Mining Industry Huge batches of samples for metals assessment 4 to 6 hours digestion time per batch Several hundred per day Throughput - a major problem! Microwave technology typically not used Microwave samples usually prepared in batches of 12 or less

16 Application - Sulfide Ore For Analysis of Ag, Ba, Cu, Fe, Pb, and Zn Zinc Concentrate Lead Concentrate Feed Bulk Feed Run of Mine

17 Initial Procedure Weigh 0.1g of sample into DV-50 centrifuge tube Add 10 ml HNO 3 Load onto 36-position turntable Insert temperature probe into reference vessel Heat using Microwave method

18 Sulfide Ore Heating Program Stage Power (%) Temp (oc( oc) Max Time (min) Hold Time (min)

19 Final Procedures Cool samples and dilute to 50 ml mark Mix well and centrifuge to settle any solids Analyze directly from 50 ml tube by ICP

20 Feed Recoveries DV-50 Ag Ba Cu Fe Pb Zn ppm wt % wt % wt % wt % wt % 50 Avg Std. Dev Hot Plate Avg. Avg Std. Dev

21 Zinc Concentrate Recoveries DV-50 Ag Ba Cu Fe Pb Zn ppm wt % wt % wt % wt % wt % 50 Avg Std. Dev Hot Plate Avg. Avg Std. Dev

22 Lead Concentrate Recoveries DV-50 Ag Ba Cu Fe Pb Zn ppm wt % wt % wt % wt % wt % 50 Avg Std. Dev Hot Plate Avg. Avg Std. Dev

23 Tissue Procedure Weigh 0.2g sample into DV-50 tube Add 5 ml of nitric acid Cap and let sit overnight Heat at 115 C C for 55 minutes Allow to cool Dilute to the 20 ml mark with DI water Vortex and dilute further for analysis as needed Aspirate directly into ICP or AA

24 NIST SRM Biological Tissue Lead Recoveries DV 50 SRM Certificate Mean Low High Mean Low High ug/g ug/g ug/g ug/g ug/g ug/g Oyster Tissue Bovine Muscle n = 10

25 NIST SRM Biological Tissue Lead Recoveries DV 50 SRM Certificate Mean Low High Mean Low High ug/g ug/g ug/g ug/g ug/g ug/g Oyster Tissue Bovine Muscle Bovine Liver n = 10

26 Blood Procedure Weigh 0.5 g of blood into DV-50 tube Add 4 ml of nitric acid and cap Heat at 115 C C for 30 minutes Add 0.8 ml of 50%H202 Heat at 115 C C for 8 minutes Dilute to 25 ml with DI water Aspirate directly into ICP-MS for 17 elements including Hg

27 Element UTAK Blood (Mid Range) Element Recoveries MDL DV 50 RSD Certificate ug/g ug/g % ug/g Ca Cd Hg Mg Pb Zn Data Courtesy of Doctor s s Data Inc., W. Chicago, IL

28 Element UTAK Blood (High Range) Element Recoveries MDL DV 50 RSD Certificate ug/g ug/g % ug/g Ca Cd Hg Mg Pb Zn Data Courtesy of Doctor s s Data Inc., W. Chicago, IL

29 Hair Procedure Place 0.2 g of cut, washed hair into DV-50 tube Add 3 ml of nitric acid and cap Heat at 115 C C for 30 minutes Dilute to the 50 ml mark with DI water Aspirate directly into ICP-MS for 42 elements including Hg, As and Se

30 China Certified Reference Material Element Element Recoveries MDL DV 50 RSD Certificate ug/g ug/g % ug/g Al As Cd Cr Hg Pb Se Zn Data Courtesy of Doctor s s Data Inc., W. Chicago, IL

31 Conclusions Fast, high throughput procedure Vessels can be disposed after use Recoveries agree with reference values Future experiments: 120-position turntable for 15 ml centrifuge tubes